WO2013185802A1 - Moteur à combustion interne - Google Patents

Moteur à combustion interne Download PDF

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Publication number
WO2013185802A1
WO2013185802A1 PCT/EP2012/061025 EP2012061025W WO2013185802A1 WO 2013185802 A1 WO2013185802 A1 WO 2013185802A1 EP 2012061025 W EP2012061025 W EP 2012061025W WO 2013185802 A1 WO2013185802 A1 WO 2013185802A1
Authority
WO
WIPO (PCT)
Prior art keywords
air
cylinder wall
piston
combustion engine
internal combustion
Prior art date
Application number
PCT/EP2012/061025
Other languages
English (en)
Inventor
Sander VAN WALLENÉ
Original Assignee
N2S B.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by N2S B.V. filed Critical N2S B.V.
Priority to PCT/EP2012/061025 priority Critical patent/WO2013185802A1/fr
Publication of WO2013185802A1 publication Critical patent/WO2013185802A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L3/00—Lift-valve, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces; Parts or accessories thereof
    • F01L3/20—Shapes or constructions of valve members, not provided for in preceding subgroups of this group
    • F01L3/205—Reed valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/02—Valve drive
    • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
    • F01L1/08—Shape of cams
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L5/00—Slide valve-gear or valve-arrangements
    • F01L5/04—Slide valve-gear or valve-arrangements with cylindrical, sleeve, or part-annularly shaped valves
    • F01L5/06—Slide valve-gear or valve-arrangements with cylindrical, sleeve, or part-annularly shaped valves surrounding working cylinder or piston
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01M—LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
    • F01M11/00—Component parts, details or accessories, not provided for in, or of interest apart from, groups F01M1/00 - F01M9/00
    • F01M11/08—Separating lubricant from air or fuel-air mixture before entry into cylinder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01M—LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
    • F01M13/00—Crankcase ventilating or breathing
    • F01M13/04—Crankcase ventilating or breathing having means for purifying air before leaving crankcase, e.g. removing oil
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B25/00—Engines characterised by using fresh charge for scavenging cylinders
    • F02B25/14—Engines characterised by using fresh charge for scavenging cylinders using reverse-flow scavenging, e.g. with both outlet and inlet ports arranged near bottom of piston stroke

Definitions

  • the present application relates to an internal combustion en- gine with a cylinder having a cylinder wall forming a main part of a combustion chamber, having a number of air inlet openings and a number of exhaust openings in the cylinder wall, a piston movably arranged in the cylinder, a crankcase, a crankshaft arranged in the crankcase, and a piston rod con- necting the crankshaft with the piston.
  • the ap ⁇ plication relates to a cooling air and/or oil cooling system, an air intake system and a damping method for an internal combustion engine.
  • a two stroke cycle includes the step of sucking an air/fuel mixture into the crankcase by vacuum that is gener- ated in the crankcase during the upward stroke of the piston.
  • the air intake is closed by a valve and the air/fuel mixture is com ⁇ pressed to a certain degree inside the crankcase.
  • an air inlet open- ing in the cylinder wall is opened by the piston in order to allow the compressed air/fuel mixture to flow into the com ⁇ bustion chamber, which is arranged in the cylinder above the piston.
  • exhaust gases are transferred to the exhaust open- ing, which usually is arranged in the top of the combustion chamber (especially in case of the use of a valve) or is ar- ranged at the side of the cylinder wall opposing the air in ⁇ let opening.
  • the air inlet opening and the exhaust opening are closed by the moving piston or optionally by a valve.
  • the air/fuel mixture is compressed or pressurized in the combustion chamber.
  • the highest compression of the air/fuel mixture has been reached and the compressed air/fuel mixture is ignited by a spark plug or a glow plug.
  • the exploding fuel/air mixture expands, i.e. its volume is significantly increased by the burning gases. Thereby the piston is forced downwards to complete the cycle and to start anew.
  • the piston moving up and down in the cylinder rotates the crankshaft by means of a piston rod mounted on the crankshaft in an asymmetric manner, i.e. eccentrically to the main axis of the crankshaft, to generate power.
  • the fuel/air mixture usually comprises specific oil additives for lubricating any moving and/or rotating elements in the cylinder or in the crankcase, especially the moving piston, the crankshaft, and the connections there between.
  • the conventional two stroke combustion engines due to the oil con ⁇ tent present in the air/fuel mixture, the conventional two stroke combustion engines have a high ratio of oil contents in the exhaust gases.
  • they are often inefficient and disadvantageous due to the high amount of fuel that es ⁇ capes through the exhaust port during the step of forcing the exhaust gases out of the exhaust opening of the combustion chamber by the fresh air/fuel mixture.
  • a sleeve valve system was developed for large two stroke diesel engines having a long cylinder casing and mechanical valves at the top of the cylinder.
  • An example of such a large diesel engine is described in EP 0 851 101 Al .
  • those diesel engines having a long piston stroke are generally not constructed for revolution speeds of the piston higher than about 600 to 700 revolutions per minute (rev./min) .
  • the engines of the state of the art are desired and re ⁇ stricted to some specific applications such as for large air- crafts, ships, or railroad engines where the weight of the engine and the revolution speed are not critical parameters.
  • the object of the invention is achieved by the internal com ⁇ bustion engine according to claim 1, the cooling air and/or oil cooling system according to claim 13, the air intake system according to claim 14 or the damping method according to claim 15.
  • Any of these aspects individually solve the above mentioned problems, in particular to provide an internal com ⁇ bustion engine having the advantages of a two stroke combus- tion engine such as, for example, being powerful, light ⁇ weight, simple in its construction, and capable of running with high revolutions.
  • the internal combustion engine according to a first aspect of the invention comprises a cylinder having a cylinder wall forming a main part of a combustion chamber, that means the cylinder wall forms a substantial part of the combustion chamber and the other part is formed by the piston moving up and down in the cylinder bore.
  • the internal combustion engine further comprises a piston movably arranged in the cylinder, a crankcase, a crankshaft arranged in the crankcase, and a piston rod connecting the crankshaft with the piston.
  • the cylinder comprises a movable cylin ⁇ der wall segment, also called “sleeve valve", for opening and closing the air inlet openings and the exhaust openings.
  • the movable cylinder wall segment moves up and down between a bottom dead centre and a seating area inside the fixed cylin- der wall arranged stationary in the engine.
  • the internal combustion engine further comprises an actuating member for actuating the movable cylinder wall segment directly or indirectly by the crankshaft. More particularly, the movable cylinder wall segment is in driving connection with the crankshaft and can be driven independently from the motion of the piston. Being in driving connection includes either to be directly connected to and driven by a cam or to be connected by means of a cam/rod-arrangement arranged be- tween the cam and the movable cylinder wall segment.
  • the use of such a cam-driven or cam/rod-driven movable cylinder wall segment allows high speed revolution engines up to about 12.000 rev./min or even more. Preferred ranges of the practi ⁇ cal maximal piston revolution speeds are about 6.000 to
  • this engine is particularly suitable for being used in, for example, motorcycles, cars, especially smaller cars, snowmobiles, jet-skis, motor-driven hand appa ⁇ ratuses such as chainsaws, outboard engines and others.
  • the pressurizing of the air or air/fuel mixture can option- ally be realized via a separate air intake system or air in ⁇ take portion.
  • the air intake portion comprises a compression chamber which is substantially sealed with regard to the crankcase.
  • the new air intake portion or the new air intake system which can optionally be used together with or in the internal com- bustion engine permits that any lubricants necessary for lu ⁇ bricating the moveable parts of an internal combustion engine can remain below the head of the moving piston, i.e. being in the crankcase and thus sealed from the fuel in the combustion chamber.
  • lubricants cannot enter into the combustion chamber or reach the exhaust system. Therefore, the pollution with burned lubricants such as oils can be reduced or omitted in the internal combustion engine according to the invention and the environmental acceptability of the exhausted gases is in the range of standard four stroke engines.
  • a green technology engine is thus possible with the new general concept of the invention.
  • the total weight of the system can be kept compa ⁇ rable or in the range of the weight of a conventional two- stroke engine and, thus, this improves the efficiency of in- ternal combustion engines also in view of economic aspects.
  • piston rings in conventional engines also called oil rings
  • piston rings are favourably ar ⁇ ranged in the circumference of the upper part of the piston.
  • the combustion chamber is sealed off the crankcase.
  • conventional engines they pass the air inlet and/or exhaust openings during every stroke of the piston.
  • the pos ⁇ sibility arises to arrange a number of piston rings (i.e.
  • the piston rings can preferably be moved within the movable cylinder wall segment and pass the transition be- tween the fixed cylinder wall segment and the movable cylin ⁇ der wall segment after the air inlet and/or exhaust openings have been closed.
  • the stress level or wear will be significantly lower than the stress level to which the piston rings of conven ⁇ tional two stroke engines are usually exposed.
  • the ad ⁇ vantageous constitution of the movable cylinder wall segment and its specific actuation by the crankshaft preferably in relation to the motion of the piston moving therein, improves the wear and the durability of the combustion engine and, particularly, of the piston rings used.
  • the internal combustion engine can be adjusted to high revolu ⁇ tions of the piston in the combustion chamber.
  • the movable cylinder wall segment can move inside a part of the fixed cylinder wall, more particularly mainly in its lower part where the air inlet openings and the exhaust openings are arranged.
  • the movable cylinder wall segment preferably provides a bore which is substantially identical to the bore of the upper part of the fixed cylinder wall seg- ment in which the combustion chamber is arranged. Therefore, the bores of the two members are designed in a manner that the piston can be moved up and down in the upper part of the fixed cylinder wall segment and in the movable cylinder wall segment.
  • the fixed cylinder wall advanta- geously has a stepwise configuration (indentation) wherein the step or indentation is complementary to the configuration of the movable cylinder wall segment.
  • the movable cylinder wall segment substitutes a part of the fixed cylinder wall in its top end position respectively, while the cylinder volume (i.e. the volume of the combustion chamber) is enlarged or expanded at the time of the downward movement of the movable cylinder wall segment.
  • This temporary change of volume of the combus ⁇ tion chamber improves the scavenging process. Therefore, it is also possible to operate the engine with a higher compres ⁇ sion ratio, especially in combination with an expansion pipe for the exhaust gases.
  • the optional stepped configuration of the fixed cylinder wall preferably provides an extra swirl of the fresh air/fuel mix ⁇ ture in the combustion chamber during the closure of the air inlet and exhaust openings. Gases in the gap between the up ⁇ per part of the movable cylinder wall segment and the lower part of the fixed cylinder wall (i.e. the landing site of the movable cylinder wall segment at the fixed cylinder wall) are pressed or forced out of the gap towards the combustion cham ⁇ ber providing the extra swirl shortly before the movable cyl ⁇ inder wall lands in its landing site during its upward mo ⁇ tion.
  • the extra swirl is advantageous for the subsequent com- bustion step in the combustion chamber due to the improved mixing of the air/fuel mixture.
  • a cooling air and/or oil cooling system for an internal combus ⁇ tion engine, especially for those as described in the first aspect.
  • the cooling air and/or oil cooling system according to the invention comprises means for cooling and recycling cooling air and/or cooling oil collected in a crankcase in a separate cooling system (e.g. one or more radiators) and for recirculating or transferring the cooling air and the oil in- to the crankcase.
  • a separate cooling system e.g. one or more radiators
  • the cooling air can, thus, be used for cooling the piston and the movable cylinder wall segment several times advantageously in a closed circulation system.
  • the cooled air is provided to the piston from its bottom, i.e.
  • a cooling air and/or oil cooling system can support high speed revolution engines up to about 12.000 rev./min or even more. Preferred ranges of the practical max ⁇ imum piston revolution speeds are about 6.000 to 10.000 rev./min, more preferably between about 6.000 to 8.000 rev . /min .
  • such a system may comprise a separator for sepa ⁇ rating air and oil, a cooling section (e.g. a radiator or cooling surfaces) for air and/or oil and a respective pipe assembly.
  • a cooling section e.g. a radiator or cooling surfaces
  • the heated air and the heated oil is preferably collected near the bottom of the cylinder or the movable cylinder wall segment because these locations are subjected to the highest temperatures.
  • the cooling air and/or oil cooling sys- tern preferably comprises a collector element. This can, for example, be a suction device for actively sucking air and/or oil, especially in the form of oil steam or oil spray, into the collector element and for transporting it to the means for cooling air and/or oil.
  • the means for cooling are preferably arranged outside the crankshaft.
  • the air cooling and/or oil cooling system comprises expedient heat exchanging members, for example one which effectively transports the heat to the surrounding atmosphere, i.e. is an air cooled heat exchanger such as a radiator.
  • the surface of the heat exchanger is pref ⁇ erably increased by using cooling ribs or the like, realizing one example embodiment of cooling means.
  • an air intake system which can preferably be used in an inter ⁇ nal combustion engine according to the first aspect.
  • the air intake system according to the invention comprises an air pump, preferably with a bellow member, which is directly or indirectly actuated by the crankshaft for compressing air or an air/fuel mixture in a compression chamber of the air intake system and transporting it to an air inlet opening of an internal combustion engine.
  • the air pump includes preferably a bellow member comprising a plate segment and a bellow segment and preferably is arranged next to the crankcase.
  • the air intake system may also be integrally provided at the crankcase.
  • the plate segment preferably a metal plate, is preferably driven by a cam and connected via a rod in order to synchronize the movement with the main cam and the crank ⁇ shaft driving the piston and the movable cylinder wall seg ⁇ ment.
  • the bellow member allows an expedient separation of the compression chamber from the crankcase.
  • the bellow is made of a flexible material so that the plate can be moved without any restriction in a wide range.
  • the plate segment is preferably guided by guiding means or a guiding member.
  • Suitable actuating means can be for example a cam follower, pusher, pile or rod guided in guiding means within a respective running socket or bushing.
  • Other preferred em ⁇ bodiments of actuating means and guiding means are for exam ⁇ ple a lever rod mounted at the crankcase and allowing a move- ment up and down to change the volume of the compression chamber like a bellow.
  • the air intake portion can be advantageously implemented in high speed revolution engines allowing up to about 12.000 rev./min or even more.
  • Preferred ranges of the practical maximum piston revolution speeds are about 6.000 to 10.000 rev./min, more preferably between about 6.000 to 8.000 rev . /min .
  • the invention relates to a damping method for an internal combustion engine comprising at least the step of damping the motion of the movable cylin ⁇ der wall segment in direction to the cylinder wall at its top dead centre by adjusting the speed of the movable cylinder wall segment in relation to the speed of the piston.
  • This damping method is especially suitable for engines with high ⁇ speed revolutions of the piston and a sleeve valve and, therefore, especially for the internal combustion engine ac ⁇ cording to the first aspect. Due to the damping method the speed of the movable cylinder wall segment is lowered by means of disengaging the combined movement of the movable cylinder wall segment and the piston at a predetermined posi ⁇ tion shortly before the movable cylinder wall segment en ⁇ gages, i.e. lands, at its seating in the fixed cylinder wall.
  • the movable cylinder wall segment is pref ⁇ erably damped by means of an air cushion, which is generated by enclosing air in a gap between the fixed cylinder wall, the upper side or the top of the movable cylinder wall seg ⁇ ment (also called the "crown") and the circumferential sur- face of the piston.
  • This air cushion significantly lowers the speed of the motion of the movable cylinder wall segment shortly before the movable cylinder wall engages at its seat in the fixed cylinder wall.
  • the actuating member comprises an asymmetric cam arranged on the crankshaft, i.e. a cam with an asymmetric circumference or surface when looking onto the cam in the direction of the crankshaft.
  • the asymmetric cam pro vides a number, that means a plurality like e.g. three four or five, of different control positions for actuating the movable cylinder wall segment.
  • Each control position can be responsible for a specific position and/or function of the movable cylinder wall segment during the operating cycle and will be explained at a specific embodiment by reference to the figures.
  • the asymmetric cam has an asymmetric circumference or surface and permits the guid ⁇ ance of a connection member connecting the cam with the movable cylinder wall segment.
  • the connection member is actuated by the rotation of the cam and is moved along the asymmetric circumference of the cam in a sliding arrangement.
  • the connection mem ⁇ ber is moved up and down and, thus, the position of the mov- able cylinder wall segment in the cylinder is adjusted in the longitudinal axis of the cylinder respectively.
  • Up and down means the direction with regard to the longitudinal axis of the cylinder in which the piston and the movable cylinder wall are moved upwards and downwards. If the cylinder is mounted in a substantial horizontal position, up indicates the direction as to the top dead centre position of the pis ⁇ ton stroke in the combustion chamber and down indicates the direction as to the bottom dead centre of the piston stroke.
  • the connection member may be a crank arm or a lever rod having a lower end connected to the crankshaft and an upper end connected to the movable cylinder wall segment.
  • the crank arm or the lever rod guides the movable cylinder wall segment within the upper end of the fixed cylinder wall in an upward and downward direction following the circumference of the cam arranged rotating around the main axis of the crankshaft.
  • the cam provides several control positions at its circumference. At the circumference means at its outer rotating surface of the cam.
  • the cam provides one and, preferably two, three or more different control positions, which can be used for accu ⁇ rately actuating the movable cylinder wall segment.
  • the moveable cylinder wall segment and the piston can be con- trolled separately, preferably by the use of a single cam.
  • the actuating member comprises a compensation arm as actuating member for damping the movement of the movable cylinder wall segment at its bottom dead cen ⁇ tre.
  • the compensation arm can be a longitudinal extendable arm, for example an arm made of a flexible material or com- prising a spring or elastomeric member.
  • the flexibility en ⁇ ables the compensation arm to improve the guidance of the movable cylinder wall segment during its longitudinal move ⁇ ment along the longitudinal axis of the fixed cylinder wall.
  • the compensation arm is biased, for example by increasing the spring pressure by a respective shape of the cam (e.g.
  • the spring pressure works in op ⁇ posite direction to the motion of the movable cylinder wall segment and permits a damping during the landing of the mov ⁇ able cylinder wall segment in its seating at the bottom dead centre .
  • the flexibility of the compensation arm permits some compensation due to installation errors or minor differences in material thicknesses, for example of the gaskets used.
  • the compensation arm can absorb changes in material thickness caused by heat expansion of the cylinder wall, the piston or the movable cylinder wall segment during the use of the engine. Changes of the material thickness may also be caused by the wear.
  • the compensation arm im ⁇ proves the lifetime of the movable cylinder wall segment and the surrounding members.
  • Exemplified materials for the piston are preferably those having a low heat expansion coefficient such as metal alloys, preferably based on titanium or aluminium, titanium, alumin- ium, but also carbon materials if lightweight materials are preferred.
  • Suitable materials for the cylinder wall are pref ⁇ erably metal alloys such as titanium or aluminium alloys. Other materials having similar heat expansion coefficients can be used as well.
  • the in- ternal combustion engine in order to improve the damping of the piston at its landing site, i.e. its seating, at the fixed cylinder wall, the in- ternal combustion engine according to another embodiment of the invention comprises a movable cylinder wall segment with an inner bore which is substantially identical to the bore of the cylinder and having a piston damping segment with a smaller bore at its lower end.
  • the piston can be moved along the longitudinal axis of the movable cylinder wall segment and can be oil damped at the bottom thereof in the piston damping segment.
  • the piston damping segment comprises a groove at the bottom of the mov- able cylinder wall segment which is filled with cooling oil.
  • the piston advantageously lands in a circular groove of the movable cylinder wall segment, forming an oil bath or oil pan.
  • oil and, thus, pressure will preferably be released through vent holes provided in the bottom of the groove in order to slowly re ⁇ note the speed of the piston and/or allowing the movement of the piston and the movable cylinder wall segment in an assem ⁇ bled manner to the bottom dead centre.
  • the compensation arm is re ⁇ sponsible for the damping action of the assembly as has been described before. Therefore, the piston damping segment im ⁇ proves the landing of the piston in the movable cylinder wall segment.
  • the motion of the moveable cylinder wall segment in its downward direction can be stopped and re ⁇ turned by this improved damping mechanism.
  • the oil damping advantageously facilitates the motion of the mov ⁇ able cylinder wall segment in upwards direction after the as ⁇ sembly has reached the bottom dead centre and is pushed up- wards again by the motion of the cam rod member or the actu ⁇ ating member. The reason is that the piston sticks to the movable cylinder wall segment because of the oil placed in the small gap between the two elements.
  • the movable cylinder wall segment follows due to the actuating force of the actuating member and, at least in the first part of the upwards movement, the sticking at the piston.
  • Another embodiment of the internal combustion engine accord ⁇ ing to the invention comprises a damping system, preferably an air damping system, for damping the motion of the movable cylinder wall segment in direction to the fixed cylinder wall at its top seating position or top dead centre.
  • the damping system works by closing the gap between the upper end of the movable cylinder wall seg ⁇ ment (also called the "crown") and the lower end of the fixed cylinder wall) while the piston closes the gap in order to provide an air cushion. This can be achieved by disengaging the movable cylinder wall segment and the piston at a posi ⁇ tion shortly before the crown will reach the seating in the fixed cylinder wall.
  • the piston is not always accelerating, it might even have negative acceleration, i.e. be decelerat ⁇ ing, depending on the way the engine is built (for instance it depends on the length of the piston rod, i.e. realizing a so called short or alternatively long-stroke type engine as known in the art, or on the duration of the exhaust timing, i.e. on the duration of time intervals reflecting an open ex ⁇ haust port or ports or a closed exhaust port or ports, pref ⁇ erably defined by the height of the respective exhaust-port) .
  • the movable cylinder wall segment will however always be slowed down, i.e. be decelerated with respect to the piston by the damping system.
  • the air in the gap between the upper end of the movable cylinder wall segment and the lower end of the fixed cylinder wall, the seating will be enclosed and more and more compressed by the upwards directed motion of the movable cylinder wall segment.
  • the pressure on top of the movable cylinder wall segment increases.
  • the improved damping mechanism permits higher revolutions as the conventional engines without such a special damping sys ⁇ tem, preferably up to 12.000 rev./min and more preferably about 6.000 to 8.000 rev./min.
  • the internal combustion engine comprises a crankcase which is at least partially filled with oil.
  • the crankcase is substantially closed and separated from the air/fuel intake and the combus- tion chamber to avoid any oil content in the exhaust gases.
  • the oil level in the crankcase is at least high enough for lubricating the crankshaft and allows pumping of some oil via an oil pump to the upper cylinder part below the piston for lubrication.
  • the oil can be pumped to the cylinder wall parts which are passed over by the piston during the up- and downward strokes.
  • the oil can be col ⁇ lected in or pumped into a circular groove into which the piston is inserted at each stroke.
  • the oil is not only used for lubrication of the moving and rotating parts in the crankcase, but is al ⁇ so used for cooling the movable cylinder wall segment and the piston.
  • a lot of oil spray will be generated inside the crank ⁇ case, for example up to one third, preferably from 1 to 20 percent, more preferably from 1 to 10 percent, of the avail ⁇ able volume of oil in the crankcase will be present in the form of oil spray.
  • the oil spray is separated in the air cooling and/or oil cooling system by means of a separator. Otherwise droplets can damage the cooling fan or the cen ⁇ trifugal air pump.
  • the internal combustion engine In order to cool the movable cylinder wall segment and/or the piston running with high revolutions in the cylinder, the internal combustion engine according to another embodiment of the invention preferably comprises a cooling air nozzle in the crankcase which is driven by a centrifugal air pump or any other expedient air pumping device. For an effective cooling action, it is preferable that the cooling air is pro ⁇ vided to the piston and/or the movable cylinder wall segment from its bottom.
  • the internal combustion engine may comprise a cooling air and/or oil cool ⁇ ing system for cooling and permitting recirculation of the cooling air and/or the oil into the crankcase.
  • the air and the oil advantageously the oil spray
  • the col ⁇ lected air/oil mixture can preferably be transferred to an external cooling system for optionally condensing the oil and separating the oil and the air by means of a separator, for example a deflector plate.
  • the oil can be collected at the bottom of the cooling system and can be pumped back to the crankcase, e.g.
  • the internal combustion engine accord ⁇ ing to the invention comprises an air pump in an air intake portion of the internal combustion engine for transporting air and/or fuel to the air inlet opening.
  • the inventive concept permits a separate compression of air or an air/fuel mixture.
  • the advantage of such a sepa- rate air intake system or air intake portion is that the air/fuel mixture does not need to contain any lubricants such as oil. Therefore, an environmentally improved burning proc ⁇ ess can be used for generating the power of the engine.
  • the internal combustion engine according to this embodiment further can have an air pump comprising a bellow member which is directly or indirectly actuated by the rotation of the crankshaft for compressing the air/fuel mixture in the air intake portion.
  • the bellow mem ⁇ ber may be supported by a plate linked to the crankshaft and working in a substantially inverted movement opposed to the piston direction.
  • Substantially inverted movement means that the bellow member is moved up and down by a cam nearly with the same revolutions as the piston, but might be timely asym ⁇ metrically synchronized with the movement of the piston.
  • the asymmetrical synchronization can improve the so called scav ⁇ enging phenomenon. This is a further advantage of the present invention, because the synchronization could be controlled separately from the movement of the piston or at least varied in a specific time frame.
  • the air intake portion comprises a guided in ⁇ take-membrane.
  • the membrane plates which are preferably made from or comprise a fibre en- hanced or reinforced material, are forced open mechanically at the moment the exhaust-pipe works at its optimal range in terms of RPMs (rev./mins), i.e. the RPMs are in the range of a resonance frequency of the exhaust pipe.
  • RPMs rev./mins
  • the membrane is preferably completely opened during the sucking of air into the combustion chamber, avoiding un- necessary drag, i.e. air resistance.
  • Balancing counter shafts can be attached to the crankshaft in order to permit an improved and smooth revolution of the crankshaft.
  • the shape and the size of such balancing counter shafts generally are adjusted by the skilled person dependent on the imbalance of the crankshaft which is caused by any of the cams or rods mounted thereon.
  • an internal combustion engine may be equipped with a cylinder having a variable combustion chamber.
  • the cylinder preferably comprises a cylinder head with a movable core element.
  • Movable means that the core ele ⁇ ment can be moved in order to enlarge the volume of the com ⁇ bustion chamber or to make its volume smaller.
  • the movable core element is movable in the same di ⁇ rection as the piston in the cylinder.
  • Another embodiment of the internal combustion engine accord ⁇ ing to the invention comprises a fuel injection pump for injecting fuel into the combustion chamber.
  • This direct injec ⁇ tion of the fuel into the combustion chamber by a fuel injec- tion pump in a cold or supercritical state is possible due to the general construction of the internal combustion engine as described before.
  • the separation between the crankcase and the combustion chamber permits the direct in ⁇ jection of the fuel into the combustion chamber. The reason is that the crankcase is separately lubricated and the air/fuel mixture does not need any lubricants anymore.
  • the air intake only passes fresh air to the combustion chamber and the fuel is injected directly into the combustion chamber.
  • the injection of the fuel may be carried out from the top of the cylinder or from a number of nozzles at the upper part of the cylinder wall.
  • the injection may be assisted by air in order to improve the air/fuel content of the mixture. This would permit the ad ⁇ justment of an improved burning condition, for example ad ⁇ justing the engine as a lean burn system.
  • the internal combustion engine may comprise a power valve at its exhaust opening. This power valve includes an adjustable valve section in order to adjust the height of the exhaust opening (exhaust port) .
  • the valve is preferably a sliding member which protrudes into the ex- haust port and is adapted to adjust the height of the exhaust port in a predefined amount, depending on the setting or ad ⁇ justment of the power valve.
  • the sliding member is preferably in a sliding engagement parallel to the fixed cylinder wall and the movable cylinder wall segment.
  • the clearance between the movable cylinder wall segment and the sliding member is similar or substantially identical at all posi ⁇ tions, preferably in a range of a view millimetres, more preferably between about 0,5 mm and 3 mm, especially between about 0,5 mm and 1,5 mm.
  • the power valve can close the ex- haust port up to about 40 percent, more preferably up to about 30 percent and is especially adjustable within a clos ⁇ ing range of about 1 percent to 40 percent, more preferably of about 1 percent to 30 percent, especially about 1 percent to 20 percent.
  • the paral ⁇ lel sliding arrangement improves the power valve according the present invention inter alia in minimizing the clearance provided between the movable cylinder wall segment and the power valve sliding member.
  • the specific design of the sliding members enables the use of such power valves at the air intake ports as well.
  • the invention enables the power valve to be de ⁇ signed sufficiently compact to be used at the air intake ports which was prohibited in conventional two stroke engines because of the lack of enough room for providing a power valve at this position.
  • the conventional power valves are di ⁇ agonally oriented with regard to the piston, so that a big clearance is present if the power valve is opened to some ex- tent.
  • the power valves can be provided substantially parallel to the movable cylinder wall segment, i.e. outside the fixed cylinder wall and in parallel direc ⁇ tion thereto.
  • the internal combus ⁇ tion engine according to the invention has an adjustable air intake port as well.
  • the internal combustion engine is preferably equipped with at least one, preferably two, three or more of the air inlet openings which are adjustable in its/their heights.
  • Adjust ⁇ able in their heights means that the size of each of the openings, i.e. the opening area in its height or width or di ⁇ ameter, is variable such as in the power valves explained be ⁇ fore.
  • the height adjustable air inlet openings are advanta- geous because they can be used to improve the scavenging phe ⁇ nomenon by adjusting the size of the opening.
  • Fig. 1 shows a cross-sectional view of an internal combustion engine according to an embodiment of the invention during a working cycle at the top dead centre of the piston;
  • Figs. 2A, 2B, and 2C show a cross-sectional view of an inter ⁇ nal combustion engine according to Fig. 1 during the same working cycle at the moment of starting the movement of the movable cylinder wall segment;
  • Fig. 3 shows a cross-sectional view of an internal combustion engine according to Fig. 1 during the same working cycle at the bottom dead centre of the piston;
  • Fig. 4 shows a cross-sectional view of an internal combustion engine according to Fig. 1 during the same working cycle at the moment of closing the air inlet openings;
  • Figs. 5A and 5B show a cross-sectional view of an internal combustion engine according to Fig. 1 during the same working cycle at the moment of closing the gap between the movable cylinder wall segment and the fixed cylinder wall;
  • Fig. 6 shows a cross-sectional view of the movable cylinder wall segment with the actuating member according to the embodiment shown in Fig. 1 ;
  • Figs. 7A to 7H show cross-sectional views of an internal com ⁇ bustion engine according to a second embodiment of the inven- tion during one operating cycle at eight different positions of the piston;
  • Fig. 8 shows a schematic cross-sectional view of an internal combustion engine according to a third embodiment of the in- vention with a cooling air and/or oil cooling system arranged thereto ;
  • Fig. 9 shows a schematic sectional plan view of an internal combustion engine according to a fourth embodiment of the in- vention with an air intake portion for an internal combustion engine ;
  • Fig. 10 shows a cross-sectional view of an air intake portion of an internal combustion engine according to a fifth embodi- ment of the invention
  • Fig. 11 shows a cross sectional view of a cylinder of a con ⁇ ventional two stroke engine comprising a power valve
  • Fig. 12 shows a cross sectional view of a cylinder of an in ⁇ ternal combustion engine with power valves according to a further embodiment of the invention
  • Fig. 13 shows a cylinder with a variable combustion chamber for the use in an internal combustion engine according to a further embodiment of the invention.
  • like reference numbers refer to like objects throughout. Objects in the diagrams are not necessarily drawn to scale.
  • Fig. 1 shows a cross-sectional view of an internal combustion engine according to an embodiment of the invention during a working cycle at the top dead centre of the piston.
  • the in ⁇ ternal combustion engine is based on a two stroke Otto cycle.
  • a cylinder 10 having a fixed cylinder wall 12, a movable cylinder wall segment 14, a combustion chamber 15, an actuating member 16 including a spring 17, a piston 18, a crankcase 20, a crankshaft 22, an asymmetric cam 24, a piston rod 26, a fuel injection pump 30, a spark 32, air inlet openings 34, exhaust openings 36 and exhaust ports 37.
  • the inter- nal combustion engine further comprises an air intake portion 40 with a plate actuating rod 42, a bellow member 44 including a plate 45 and a bellow 46, a compression chamber 47, a guiding means 48, and an air inlet nozzle 50.
  • a cooling air nozzle 61 In the crank- case 20, a cooling air nozzle 61, a cooling air and/or oil collecting member 62, and an oil pump 64 are provided.
  • Fig. 1 shows the position of a kick starter 70, a primary gear shaft 80, a secondary gear shaft 85, and a gear- selector drum 90.
  • the piston 18 is at its top dead centre so that the piston rod 26 is in upright position.
  • the piston is fully disengaged from the movable cylinder wall segment.
  • the air inlet open ⁇ ings 34 and the exhaust openings 36 are closed by the movable cylinder wall segment 14. At this time, the air/fuel mixture in the combustion chamber 15 is ignited by the spark 32 and the burning fuel suddenly expands its volume.
  • the piston 18 is pushed downwards and rotates the crankshaft via the piston rod 26.
  • the air intake portion 40 is in a status of sucking air into the compression chamber 47 via the air inlet nozzle 50.
  • the plate 45 of the bellow member 44 is in a position of its low- er dead centre. That means that the compression chamber 47 has a volume at its maximum level.
  • the driving force for sucking air is the low pressure, preferably vacuum, in the compression chamber 47.
  • the Fig. 2A shows the same internal combustion engine as shown in Fig. 1 during the moment of opening the moveable cylinder wall segment 14.
  • the upper surface of the piston 18 reaches the upper end of the movable cylin- der wall segment 14.
  • the piston 18 lands in the piston damping segment 119 provided at the bottom end of the movable cylinder wall segment 14.
  • the movable cylinder wall segment is slightly moved by an air pressure wave produced by the circular shaped bottom of the skirt of the piston 18, which substantially corresponds to the shaped circular damping segment 119 of the movable cylinder wall segment 14.
  • the bottom of the circular damping segment 119 is shaped in such a manner that the pres ⁇ sure will increase slowly.
  • the pressure in the gap will increase substantially to the pressure of the combustion gas present in the combustion chamber 15.
  • the combustion gas pressure brings the movable cylinder wall segment 14 to a speed which is substan ⁇ tially the same as the speed of the piston.
  • This permits a gentle engagement of the piston 18 in the movable cylinder wall segment 14 and also an improved adjustment or matching of the speed of both parts.
  • the piston 18 lands in an oil bath for damping the motion of the piston 18. This is shown in Fig. 2B which is an enlarged view of the part "a" of Fig.
  • the piston damping segment 119 essentially consist of the circu ⁇ lar groove which has the same shape as the bottom of the pis ⁇ ton 18 with the circular protrusion 118.
  • the groove is filled with cooling oil which is also used for lubricating the motion of the piston 18 in the movable cylinder wall segment 14 having an inner wall 114 made from a material having a low heat expansion coefficient such as titanium.
  • vent holes are provided for permitting the flow of oil there trough. The flow of oil through the vent holes reduces the pressure build up by the landing piston 18 in the groove 119. Thus, the speed of the piston 18 is slowly reduced to provide an oil damped landing of the piston 18 at the piston damping segment 119.
  • the piston 18 moves together with the movable cylinder wall segment 14 in an assembled manner downwards in the direction to the bottom dead centre after its landing in the piston damping segment 119.
  • the piston has a number of piston rings 125 to avoid that oil can escape into the combustion chamber.
  • Three piston rings are provided.
  • Fig. 2C shows small circular grooves 135 in the wall of the fixed cylinder in the segment of the small gap 130 opened by means of the air wave of the skirt of the piston 18 generated by the downwards mo- tion of the piston 18.
  • the small circular grooves 135 are connected with the exhaust opening and permit an improved transport of the hot combustion gases to the exhaust opening.
  • the groves 135 lead hot combustion gasses which have leaked past the movable cylinder wall segment 14 without upper rings to the exhaust side. Thereby, the combustion gas ⁇ es are prevented from being mixed with the fresh air/fuel mixture in the intake ports.
  • Fig. 3 shows a cross-sectional view of an internal combustion engine according to Fig.
  • Fig. 4 shows a cross-sectional view of an internal combustion engine according to Fig. 1 during the same working cycle at the moment of closing the air inlet openings 34 in the cylin ⁇ der 10 by the movable cylinder wall segment 14.
  • the exhaust openings 36 are still open to a reasonable amount and some of the gases in the exhaust pipe are forced back into the combustion chamber 15 of the cylinder due to the pressure wave created by the design of the expansion pipe. This further improves the next ignition process, be ⁇ cause it is known that small amount of exhaust gases can serve as a catalyst for the next combustion step.
  • the en ⁇ larged view in Fig. 4 shows an extra clearance CI between the movable cylinder wall segment 14 and the upper part of the lower fixed cylinder wall.
  • This clearance is advantageous be- cause of the possibility of tilting of the movable cylinder wall segment 14 in some extent.
  • the movable cylinder wall segment 14 can slide inside the fixed cylinder wall 12 without touching it.
  • the clearance CI avoids wear and tear in the cylinder wall segment 14 as well as in the fixed cylinder wall 12.
  • Fig. 5A shows a cross-sectional view of an internal combus ⁇ tion engine according to Fig. 1 during the same working cycle at the moment of closing the gap between the movable cylinder wall segment 14 and the fixed cylinder wall 12.
  • Fig. 6 shows a cross-sectional view of the movable cylinder wall segment 14 with the actuating member 16 according to the embodiment shown in Fig. 1.
  • the movable cylinder wall 14 comprises at its bottom section a piston damping segment with grooves 119 and vent holes 120 for oil damping during the downwards stroke of the piston (not shown) .
  • the movable cyl ⁇ inder wall 14 comprises an actuating member 16 with a spring 17 as a compensation arm mounted between the cam (not shown) and the movable cylinder wall segment 14.
  • the arm is con ⁇ nected by a wheel 200 or a sliding device like a rocker arm to the cam in order to follow the circumference of the cam. It is further connected to the movable cylinder wall segment 14 by a connecting member 210 in a non-rigid or slightly flexible manner in order to allow some compensation motions of the actuating member 16.
  • the compensation motions are limited by the buffers 220 and 230 in order to restrict the movement of the movable cylinder wall segment 14 during the damping of the piston (not shown) in the piston damping segment 119.
  • the buffers 220 and 230 allow a maximal movement MAX of the actuating member 16 in a range of few millimetres, preferably about 3 to 5 mm in the exemplified internal combustion engine. Thereby, it can be secured that the piston (not shown) rises too much about the upper side of the movable cylinder wall segment 14 during the upwards stroke.
  • the angle MIN identifies the mini ⁇ mum angle which can be used for compensation activity. If the actuating member is in this position, the movable cylinder wall segment 14 is moved in an upwards direction.
  • the movable cylinder wall 14 comprises skirts 250 to prevent it from fluttering within the cylinder bore
  • the skirts 250 are provided at both sides of the actuating member in this embodiment, but can also be provided at one side only.
  • the retainer 240 is a rotation preventing member in order to hinder the movable cylinder wall segment 14 to start rotating within the fixed cylinder wall (not shown) .
  • the retainer can be moved in a respective guiding rail (not shown) .
  • FIGs. 7A to 7H an internal combustion engine according to a second embodiment of the invention is shown during one op- erating cycle.
  • the Figures show a cylinder 12 with an air inlet opening (not shown) and an exhaust port 37, an asymmetric cam 24, the piston rod 26, the actuating member 16, the piston 18, and the movable cylinder wall segment 14 at eight different positions of the piston 18.
  • the sequence of eight views explains the operation of the asymmetric cam and the actuating member during the operation cycle in greater detail .
  • Fig. 7A the piston is moved downwards, i.e. in the direc- tion of the bottom dead centre.
  • the situation 3 mm before opening the exhaust port 37 is shown.
  • the detail Ai shows the complete sealing of the movable cylinder wall segment 14 and the cylinder wall 12 because of the high spring pressure gen ⁇ erated by the spring 17 of the actuating member 16 which is held in position 1 by the asymmetric cam 24.
  • the detail Bi shows the circular groove of the piston damping segment 119. At this moment, some pressure is being build up in the groove, though there is still some space for air to escape at points Ci and Di .
  • Fig. 7B the piston is moved downwards by 1 mm, whereby the sealing at detail Ai is still present, while the air pressure at the piston damping segment 119 is being build up due to the smaller gap at points Ci and Di .
  • the spring pressure of the spring 17 is reduced to some extent.
  • the actuating member changes into position 2, that means in a position, in which the tension of the movable cylinder wall segment is reduced.
  • the Fig. 7C shows the situation 1 mm before opening the ex ⁇ haust port 37. Due to the asymmetric circumference of the cam 24 (see detail D 2 ) , the actuating member 16 is almost com ⁇ pletely loose from the asymmetric cam 24 because of the con- tact with buffer 220 (see detail C 2 ) ⁇ This position of the actuating member 16 is called position 3. In addition, the piston 18 is almost landed in the groove of the piston damp ⁇ ing segment 119. Thus, the air is fully compressed in the circular groove.
  • the Fig. 7E shows the situation in the operating cycle in which the exhaust port 37 is fully opened and the piston 18 is at its bottom dead centre.
  • the actuating member 16 is again in position 1 by means of the raised pressure of the cam 24 against the actuating member 16.
  • the force of the spring 17 increases at the same time and helps the movable cylinder wall segment 14 getting upwards after having passed the bottom dead centre.
  • Fig. 7G shows the point at which the exhaust port is closed (please see detail A 4 ) by means of the movable cylinder wall segment 14. From this point of the operating circle, the mov ⁇ able cylinder wall segment 14 will start to slow down due to the air compression build up above the crown of the movable cylinder wall segment 14.
  • Fig. 7H the situation approximately 1 mm before closing the gap between the crown of the movable cylinder wall seg ⁇ ment 14 and the fixed cylinder wall 12 is shown (A 4 ) .
  • the spring pressure is completely loosened by changing the shape of the circumference of the cam 24 at this time so that the actuating member is in position 3 again.
  • the actuating member 16 is preferably some tenth of a millimeter (detail B 4 ) away from the circumference of the cam 24 at this point of the op ⁇ erating circle. Due to the lowering of the force acting on the movable cylinder wall segment 14, the piston 18 can es- cape the movable cylinder wall segment 14 so that the piston 18 is moved faster compared to the movable cylinder wall seg ⁇ ment 14. Thus the air in the gap between the crown of the movable cylinder wall segment 14 and the fixed cylinder wall 12 (see detail A 4 ) is blocked from escaping. The remaining air acts as an air damping system. During the closing of the gap by means of bringing the actuating member in position 1 by means of increasing the cam height of the cam 24, the closing movable cylinder wall segment, the air acts as an air cushioning system improving the long-life of the engine.
  • FIG. 8 shows a schematic cross-sectional view of an internal combustion engine 1 according to a third embodiment of the invention with a cooling air and/or oil cooling system 60 arranged thereto.
  • the cooling air and/or oil cooling system 60 comprises a cooling air nozzle 61, a cooling air and/or oil collecting member 62, a centrifugal air pump 63 (or optional an air pumping device with another constructional design) , an oil pump 64, a hot air pipe 65, a cool air pipe 66, a cool oil pipe 67, an oil cooler connecting pipe 68, and a lubricating pipe 69.
  • the cooling air and/or oil collecting system comprises an air cooling section X, an air/oil separation section Y, and an oil cooling section Z for separating and cooling the air and/or oil components present in the circulation system of the internal combustion engine 1 according to the invention.
  • Cooling and lubricating oil 0 is cooled in the oil cooling section Z and delivered through the cool oil pipe 67 to the crank case 20 which is partly filled with oil 0.
  • the oil is usually collected at the bottom of the crankcase and pumped by the oil pump 64 optionally provided with an oil filter (not shown) via the oil cooler connecting pipe 68 back to the hot oil inlet W at the oil cooling section Z for cooling the oil and via the lubricating pipe 69 to the ports and bearings for lubrication of the piston and movable parts of the en ⁇ gine .
  • the centrifugal air pump 63 pumps cooling air via the cooling air nozzle 61 to the bottom of the piston 18 and movable cyl ⁇ inder wall segment 14 in order to cool the hottest parts of the moving elements in the engine.
  • This additional air cool- ing allows higher revolution speeds than in conventional engines without additional air cooling.
  • the cooling air is col ⁇ lected in the cooling air and/or oil collecting member 62 which is directly placed in the upper part of the crankcase 20 and below the movable cylinder wall segment.
  • the collect- ing member sucks hot air and oil spray in order to transport them via the hot air pipe 65 into the air/oil separation sec ⁇ tion Y.
  • the air and the oil are separated by means of a number of deflecting plates so that the oil in form of droplets is collected at its bottom and passed to the oil cooling section Z and the hot air is collected at the up ⁇ per part of the separation section Y and transferred to the air cooling section X.
  • the cooled air is transported via the cool air pipe 66 to the centrifugal air pump 61 to start a new cooling cycle.
  • Fig. 9 shows a schematic sectional plan view of an internal combustion engine according to a fourth embodiment of the invention with an air intake portion 40 for an internal combustion engine.
  • the air intake portion 40 comprises a bellow member consisting of a metal plate 45 and a rubber bellow 46, two plate guidance rods 48 for guiding the motion of the plate, and an air inlet nozzle 50 (usually called “carb") with membrane members 51 as a check-valve with an air inlet choke .
  • the metal plate 45 and the rubber bellow 46 can be moved down and up, that means out of the plane of the sheet in order to compress the air in the compression chamber (above the sheet plane) and forcing the compressed air into the transfer ports Al, A2, A3 and the boost ports B (one is shown in this em ⁇ bodiment) .
  • the end of the port Al, A2, A3 and B are the air inlet openings into the cylinder 10 which are opened and closed by the movable cylinder wall segment 14.
  • the air is sucked into the air inlet nozzle 50 by means of an under ⁇ pressure in the compression chamber of the air intake portion 40 and transferred via the membrane members 51 and the trans- fer ports Al, A2, A3 and the boost port B to the combustion chamber (not shown) arranged above the piston 18.
  • Fig. 10 shows a cross-sectional view of an air intake portion 40 of an internal combustion engine according to a fifth em- bodiment of the invention.
  • the air intake portion 40 com ⁇ prises a bellow member 44 consisting of a metal plate 45 and a rubber bellow 46, a plate guidance member 48 for guiding the motion of the plate, an plate actuating rod 42, a bellow cam 43 and an air inlet nozzle 50 (usually called “carb”) with membrane members 51 as a check-valve with an air inlet choke.
  • the air intake portion 40 is arranged next to the cyl ⁇ inder 10 with a fixed cylinder wall 12 and air inlet openings 34.
  • the bellow cam 43 is driven by means of the main cam 24 or the crankshaft (not shown) , for example by means of a driving belt or chain (not shown) . Alternatively, it can also be driven by means of other mechanical and electrical solu ⁇ tions .
  • the metal plate 45 and the rubber bellow 46 can be moved down and up like a bellow in order to compress the air in the com ⁇ pression chamber (47) and pushing the compressed air to the air inlet openings 34.
  • the motion is in this embodiment guid ⁇ ed by means of the plate guidance member 48 which holds the metal plate 45 via a lever arm.
  • the highest compression is achieved in the position "C" of the metal plate while the position “S” means that a vacuum is provided in the compression chamber to suck fresh air via the air inlet nozzle 50 and the membrane 51 into the compression chamber (as shown in Fig. 10) .
  • the embodiment of Fig. 10 allows an advantageous compact con ⁇ struction of the air intake portion. Especially, a short dis ⁇ tance between intake ports and inlet nozzle 50 can be pro ⁇ vided. Moreover, compared to the embodiment shown in Fig. 9, no lubrication is necessary as guidance rods are not provided in this embodiment.
  • This embodiment is additionally advanta ⁇ geous in providing a shorter distance between the intake ports and the carburator or air intake nozzle.
  • Fig. 11 shows a cross sectional view of a cylinder 312 of a conventional two stroke engine comprising a power valve 338 at its exhaust opening 336.
  • the engine has a cylinder 312, an air inlet opening 334 with a fixed height B' at its air in ⁇ take port 335, an exhaust pipe 333, an exhaust opening 336, and a power valve 338 at its exhaust opening 336.
  • the power valve 338 with a sliding member can be diagonally slide into the upper part of the exhaust opening 336 to re ⁇ place the free upper part of the opening with a side wall el ⁇ ement 339 in a specific amount. If the sliding member is en ⁇ gaged at its lowest position (position A' ) , the exhaust port has its minimum port height. The port height can be freely adjusted by pulling the sliding member backwards so that the port opening is opened to some extent (position D' ) or to ⁇ tally. As the sliding member slides in a diagonal direction, there remains a clearance C from the piston (not shown) in this conventional two stroke engine.
  • Fig. 12 shows a cross sectional view of a cylinder 12 of an internal combustion engine according to a further embodiment of the invention.
  • the engine comprises a cylinder 12 with a fixed cylinder head 122 and a movable cyl ⁇ inder wall 14, an air intake port 35 with an air inlet open- ing 34, an exhaust opening 36, an intake power valve 38 at the air intake port 35 and a power valve 39 at the exhaust opening 36.
  • the intake power valve 38 and the power valve 39 include an adjustable valve section in order to adjust the height of the air inlet opening 34 at the air intake port 35 and the ex ⁇ haust opening (exhaust port) 36 by a specific adjusting height A' ' and B' ' , respectively.
  • the intake power valve 38 and the power valve 39 are preferably sliding members which protrude into the exhaust port and intake port, respectively.
  • the sliding members are in a sliding engagement parallel to the fixed cylinder wall 12 and the movable cylinder wall seg ⁇ ment 14.
  • the clearance C ' between the movable cylinder wall segment 14 and the intake power valve 38 and the power valve 39 is similar or substantially identical at all posi ⁇ tions .
  • the parallel sliding arrangement improves the power valve as used according the present invention especially in the less clearance provided between the movable cylinder wall segment and the power valve sliding member.
  • the specific design of the sliding members enables the use of such power valves at the air inlet ports as well. Thereby, the handling is improved, especially with regard to a wider power-band ad ⁇ justment or a better efficiency.
  • Fig. 13 shows a cylinder 12 with a variable combustion cham- ber 18 for the use in an internal combustion engine according to a further embodiment of the invention.
  • the cylinder 12 comprises a cylinder head 122 with a movable core element 412 including a spark 32.
  • the movable core is movable in the same direction as the piston 18 moves in the cylinder 12, thereby changing the volume of the combustion chamber 15. If the movable core element 412 is moved out of the cylinder head 122, the volume will be bigger, while the volume will be smaller if the movable core element 412 is pushed into the cylinder 12. Thereby the efficiency of the engine can be advanta ⁇ geously adjusted by varying the volume of the combustion chamber .
  • the movable core element 412 is sealed against the cylinder head 122 by means of a number of seals 420.
  • the cylinder head 122 comprises an upper hydraulic oil chamber 430 including the oil channel 435 and a bottom hydraulic oil chamber 440 including the oil channel 445.
  • the upper hydraulic oil cham ⁇ ber 430 is arranged as a groove around the movable core mem ⁇ ber 412.
  • the bottom hydraulic oil chamber 440 is arranged in the same manner around the core member 412.
  • the movable inner core member has one or more protrusions 450 including a seal 420 to avoid any leakage from the upper oil chamber 430 to the bottom oil chamber 440.
  • the position of the movable core element 412 can be adjusted. If more hydraulic oil is pumped into the upper oil chamber 430, the combustion chamber volume will be decreased and it will be increased by means of pumping oil from the upper oil chamber 430 into the bottom oil chamber 440.
  • the air intake portion can be a compressor or a 24/7-intake system instead of the herein described bel ⁇ low system.
  • the air intake portion can be a compressor or a 24/7-intake system instead of the herein described bel ⁇ low system.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Cylinder Crankcases Of Internal Combustion Engines (AREA)

Abstract

La présente invention concerne un moteur à combustion interne (1) comprenant un cylindre (10) ayant une paroi de cylindre (12) formant une pièce principale d'une chambre de combustion (15), un certain nombre d'ouvertures d'arrivée d'air (34) et un certain nombre d'ouvertures d'échappement (36) dans la paroi de cylindre (12), un piston (18) placé mobile dans le cylindre (10), un carter de vilebrequin (20), un vilebrequin (22), et une tige de piston (26) reliant le vilebrequin (22) au piston (18), le cylindre (10) comprenant un segment de paroi de cylindre mobile (14) pour ouvrir et fermer les ouvertures d'arrivée d'air (34) et/ou les ouvertures d'échappement (36) et un élément d'actionnement (16) pour actionner le segment de paroi de cylindre mobile (14) directement ou indirectement par le vilebrequin (22). De plus, l'invention concerne un système à air de refroidissement et/ou de refroidissement d'huile (60), un système d'admission d'air (40) et un procédé d'amortissement destinés à un tel moteur.
PCT/EP2012/061025 2012-06-11 2012-06-11 Moteur à combustion interne WO2013185802A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/EP2012/061025 WO2013185802A1 (fr) 2012-06-11 2012-06-11 Moteur à combustion interne

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Application Number Priority Date Filing Date Title
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019012285A1 (fr) * 2017-07-13 2019-01-17 Knight Brian R Agencement de piston amélioré

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB133232A (fr) *
GB191004333A (en) * 1910-02-21 1911-01-12 James Dennis Roots Improvements in the Valves and Valve Gear of Internal Combustion Engines.
GB191210944A (en) * 1912-05-08 1912-09-26 Angus Munro Robinson Improvements in Valve-mechanism for Internal-combustion Engines.
US1639898A (en) * 1926-04-29 1927-08-23 Arthur S Piers Internal-combustion engine
GB580398A (en) * 1945-01-18 1946-09-05 Clement Tipton Rhodes Improvements in or relating to sleeve valve two stroke internal combustion engines
US2808039A (en) * 1955-10-11 1957-10-01 Ajax Iron Works Air-cooled piston
EP0851101A1 (fr) 1996-12-24 1998-07-01 Wärtsilä NSD Schweiz AG Moteur diesel

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB133232A (fr) *
GB191004333A (en) * 1910-02-21 1911-01-12 James Dennis Roots Improvements in the Valves and Valve Gear of Internal Combustion Engines.
GB191210944A (en) * 1912-05-08 1912-09-26 Angus Munro Robinson Improvements in Valve-mechanism for Internal-combustion Engines.
US1639898A (en) * 1926-04-29 1927-08-23 Arthur S Piers Internal-combustion engine
GB580398A (en) * 1945-01-18 1946-09-05 Clement Tipton Rhodes Improvements in or relating to sleeve valve two stroke internal combustion engines
US2808039A (en) * 1955-10-11 1957-10-01 Ajax Iron Works Air-cooled piston
EP0851101A1 (fr) 1996-12-24 1998-07-01 Wärtsilä NSD Schweiz AG Moteur diesel

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019012285A1 (fr) * 2017-07-13 2019-01-17 Knight Brian R Agencement de piston amélioré

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